[EdHolland]

I made some progress today, of sorts.

First, I powered up with all the valves except the rectifier, checked that they were all heating etc. Then I added the rectifier. With a 60W bulb, the highest power I have available, there was around 70V HT, no sound or signs of life. With no other option, I went for direct connection, measuring everything carefully. HT settled around 380V, but no sounds from the speaker or response to tuning. Nothing untoward, glowing red or emitting blue smoke.

Further investigation showed the audio O/P stage is alive. I could hear crackles when probing the type 42 output valves, and a distinct hum with a probe on the grid of the type 42 driver. This is good news for both my interstage and output transformers. However, I get no response probing at the volume control, or around the type 77 tube AF preamplifier that feeds the driver, which ought to be pretty sensitive, so something is amiss here. It could be a wiring error, or something else, but I ran out of time for diagnostics.

Lastly, the RF stages are drawing current, since the shadow meter's shadow grew large as the set warmed up. Tuning around produced no changes, but there was no aerial connected. I will at least check for oscillator activity on the Broadcast Band using another set as detector when I get another chance to tinker.

Hopefully more tomorrow.